1. Field of the Invention
The present disclosure relates to a fuel cell stack.
2. Discussion of the Background
For example, a solid polymer electrolyte fuel cell includes a power generation cell, in which an electrolyte membrane-electrode assembly (MEA) is sandwiched between a pair of separators, the electrolyte membrane-electrode assembly including an electrolyte membrane formed of a polymer ion exchange membrane, and anode and cathode electrodes that are disposed on both sides of the electrolyte membrane. A fuel cell stack, in which a predetermined number (for example, hundreds) of power generation cells are usually stacked, is used as an in-vehicle fuel cell stack, for example.
In the above-described fuel cell, a fuel gas passage for passing a fuel gas to the anode electrode is provided on the surface of one of the separators, and an oxidant gas passage for passing an oxidant gas to the cathode electrode is provided on the surface of the other of the separators. In addition, a cooling medium passage for passing a cooling medium is disposed between adjacent power generation cells or between adjacent cells in a predetermined number of power generation cells along the surface direction of the separators.
In some fuel cells, a fuel gas supply communication hole which supplies a fuel gas to a fuel gas passage, a fuel gas discharge communication hole which discharges a consumed fuel gas from the fuel gas passage, an oxidant gas supply communication hole which supplies an oxidant gas to an oxidant gas passage, an oxidant gas discharge communication hole which discharges a consumed oxidant gas from the oxidant gas passage, a cooling medium supply communication hole which supplies a cooling medium to a cooling-medium passage, and a cooling medium discharge communication hole which discharges a used cooling medium from the cooling medium passage are formed as through holes in the stacking direction, i.e., a so-called internal manifold is formed.
In this type of internal manifold mold fuel cell, a connecting structure for communicating each communication hole to an external manifold member is used in at least one of the end plates. For example, the fuel cell disclosed in Japanese Unexamined Patent Application Publication No. 2005-259427 includes a stacked body of the cells 1 as illustrated in FIG. 9. A terminal 2, an insulator 3, and a pressure plate 4 are disposed at one end of the structure of stacked body of the cells 1.
The cell 1 has a MEA5, on both sides of which a first separator 6 and a second separator 7 are disposed, respectively. A conduit member 8 has a tube portion 8b which penetrates through a hole of the pressure plate 4, and has a flange 8a on the side of the pressure plate 4 that faces the stacked body. The flange 8a is housed in a housing portion of the terminal 2 and the insulator 3, and is connected via an end-face seal 9 to the stacked body of the cells 1 as a passage.